Abstract:

According to one embodiment, an information recording apparatus which
records content compliant with a second DVD standard on an information
storage medium, the second DVD standard being a DVD standard later than a
first DVD standard defined for a first image quality and being defined
for a second image quality higher than the first image quality, includes
a determination unit configured to determine whether narrow burst cutting
area (NBCA) of the information storage medium is valid or not, and
whether supported maximum recording speed of the information storage
medium is triple speed or more of a predetermined recording speed, and a
recording unit configured to perform real-time recording of the content
compliant with the second standard on the information storage medium on
the basis of the determination.

Claims:

1. An information recording apparatus configured to record content
compliant with a first and second DVD standard on an information storage
medium, the second DVD standard being defined for a higher image quality
than the image quality of the first DVD standard, the apparatus
comprising:a reading unit configured to read information recorded on the
information storage medium;a determination unit configured to determine
whether the narrow burst cutting area (NBCA) of the information storage
medium is valid or not, and whether the supported maximum recording speed
of the information storage medium is triple speed, three times faster of
a normal recording speed of the first DVD standard, or more, based on the
information read by the reading unit; anda recording unit configured to
perform real-time recording of the content compliant with the second DVD
standard on the information storage medium satisfying a condition that
the NBCA of the information storage medium is valid and the supported
maximum recording speed of the information storage medium is triple speed
or more of the normal recording speed of the first DVD standard.

2. An information recording apparatus of claim 1, further comprising:a
second recording unit configured to record the content compliant with the
second DVD standard on an external storage device in real time at a
recording speed slower than triple speed of the normal recording speed of
the first DVD standard, on the condition that the NBCA of the information
storage medium is valid and the supported maximum recording speed of the
information storage medium is slower than triple speed of the normal
recording speed of the first DVD standard.

3. An information recording method configured to record content compliant
with a first and second DVD standard on an information storage medium,
the second DVD standard being defined for a higher image quality than the
image quality of the first DVD standard, the method comprising:reading
information recorded on the information storage medium;determining
whether the narrow burst cutting area (NBCA) of the information storage
medium is valid or not, and whether the supported maximum recording speed
of the information storage medium is triple speed or more of a normal
recording speed of the first DVD standard, based on the read information;
andperforming real-time recording of the content compliant with the
second DVD standard on the information storage medium satisfying a
condition that the NBCA of the information storage medium is valid and
the supported maximum recording speed of the information storage medium
is triple speed or more of the normal recording speed of the first DVD
standard.

4. An information recording method of claim 3, whereinthe content
compliant with the second DVD standard is recorded on an external storage
device in real time, and the content compliant with the second DVD
standard recorded on the external storage device is recorded on the
information storage medium at a recording speed less than triple speed of
the normal recording speed of the first DVD standard, on the condition
that the NBCA of the information storage medium is valid and the
supported maximum recording speed of the information storage medium is
less than triple speed of the normal recording speed of the first DVD
standard.

5. An information playback apparatus configured to play back an
information storage medium recording content compliant with a first and
second DVD standard, the second DVD standard being defined for a higher
image quality than the image quality of the first DVD standard, the
apparatus comprising:a reading unit configured to read information
recorded on the information storage medium;a determination unit
configured to determine whether the narrow burst cutting area (NBCA) of
the information storage medium is valid or not, and whether the supported
maximum recording speed of the information storage medium is triple speed
or more of a normal recording speed of the first DVD standard, based on
the information read by the reading unit; anda playback unit configured
to perform triple-speed playback of the content compliant with the second
DVD standard from the information storage medium satisfying a condition
that the NBCA of the information storage medium is valid and the
supported maximum recording speed of the information storage medium is
triple speed or more of the normal recording speed of the first DVD
standard.

6. An information playback apparatus of claim 5, whereinthe playback unit
is configured to perform triple-speed playback of the content compliant
with the second DVD standard from the information storage medium
satisfying a condition that the NBCA of the information storage medium is
valid and the supported maximum playback speed of the information storage
medium is three times faster or more of the normal playback speed of the
first DVD standard.

7. An information playback method configured to play back an information
storage medium recording content compliant with a first and second DVD
standard, the second DVD standard being defined for a higher image
quality than the image quality of the first DVD standard, the method
comprising:reading information recorded on an information storage
medium;determining whether the narrow burst cutting area (NBCA) of the
information storage medium is valid or not, and whether the supported
maximum recording speed of the information storage medium is triple speed
or more of a normal recording speed of the first DVD standard, based on
the read information; andperforming triple-speed playback of the content
compliant with the second DVD standard from the information storage
medium satisfying a condition that the NBCA of the information storage
medium is valid and the supported maximum recording speed of the
information storage medium is triple speed or more of the normal
recording speed of the first DVD standard.

8. An information playback method of claim 7, whereinthe content compliant
with the second DVD standard is configured to be played back at triple
speed from the information storage medium satisfying a condition that the
NBCA of the information storage medium is valid and the supported maximum
playback speed of the information storage medium is triple speed or more
of the normal playback speed of the first DVD standard.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application is based upon and claims the benefit of priority
from Japanese Patent Application No. 2007-120107, filed Apr. 27, 2007,
the entire contents of which are incorporated herein by reference.

BACKGROUND

[0002]1. Field

[0003]One embodiment of the invention relates to an information recording
apparatus and an information recording method which record content
compliant with a second DVD standard, which is a DVD standard later than
a first DVD standard defined for a first image quality and is defined for
a second image quality higher than the first image quality, on image
storage media such as DVD-R/RWs.

[0004]Further, one embodiment of the invention relates to an information
playback apparatus and an information playback method which play back HD
DVD content compliant with the second DVD standard from information
storage media such as DVD-R/RW.

[0005]2. Description of the Related Art

[0006]Various products compliant with the normal DVD standard (the
first-generation DVD standard) defined for the standard image quality
have already been widely spread. With increase in image compression
technique in these several years, there are users' and content providers'
demands for further improvement of image quality. Further, in addition to
demands for accomplishment of higher image quality, content providers
demand environment for providing more attractive content to users by
expansion of the content, such as a more colorful menu and improved
interactivity in content such as menu screens and extra images, including
main titles. To deal with such demands, Jpn. Pat. Appln. KOKAI Pub. No.
2006-260611 discloses a technique concerning an DH DVD standard
(second-generation DVD standard) to achieve provision of more attractive
content.

[0007]While the environment for providing HD DVD content compliant with
the HD DVD standard is ripe as described above, the convenience of media
(DVD-R/RW) compliant with the normal DVD standard is still high.
Therefore, there is a demand for a technique of appropriately recording
HD DVD content on DVD-R/RWs and the like, and appropriately playing back
HD DVD content recorded on DVD-R/RW.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008]A general architecture that implements the various feature of the
invention will now be described with reference to the drawings. The
drawings and the associated descriptions are provided to illustrate
embodiments of the invention and not to limit the scope of the invention.

[0009]FIG. 1 is a diagram illustrating relationship between linear
velocity of triple-speed playback and data transfer rate performed by an
information recording and playback apparatus according to an embodiment
of the invention.

[0010]FIG. 2 is a diagram illustrating an example of a data playback
circuit of the information recording and playback apparatus according to
the embodiment.

[0011]FIG. 3 is a diagram illustrating an example of a equalizer
characteristic in triple-speed playback according to the embodiment.

[0012]FIG. 4 is a diagram illustrating an example of a triple-speed
playback servo circuit of the information recording and playback
apparatus according to the embodiment.

[0013]FIG. 5 is a diagram illustrating an example of a focus servo
characteristic in the axial direction for triple-speed playback according
to the embodiment.

[0014]FIG. 6 is a diagram illustrating an example of a tracking servo
characteristic in the radial direction according to the embodiment.

[0015]FIG. 7 illustrates a disc discrimination processing by which
triple-speed recording can be performed by the information recording and
playback apparatus according to the embodiment.

[0016]FIG. 8 is a flowchart illustrating recording processing of HD DVD
content on a disc which supports only recording speed lower than
triple-speed recording by the information recording and playback
apparatus according to the embodiment.

[0017]FIG. 9 is a flowchart illustrating playback processing of HD DVD/VR
content recorded on a disc by the information recording and playback
apparatus according to the embodiment.

[0018]FIG. 10 is a block diagram illustrating a schematic structure of the
information recording and playback apparatus according to the embodiment.

DETAILED DESCRIPTION

[0019]Various embodiments according to the invention will be described
hereinafter with reference to the accompanying drawings. In general,
according to one embodiment of the invention, an information recording
apparatus which records content compliant with a DVD standard for high
image quality on an information storage medium comprises: a reading unit
configured to read information recorded on an information storage medium;
a determination unit configured to determine whether the NBCA of the
information storage medium is valid or not, and whether supported maximum
recording speed of the information storage medium is triple speed, i.e.
three times faster of a normal recording speed, or more, based on the
information read by the reading unit; and a recording unit configured to
perform real-time recording of the content compliant with the DVD
standard for high image quality on the information storage medium which
satisfies a condition that the NBCA of the information storage medium is
valid and the supported maximum recording speed of the information
storage medium is triple speed or more.

[0020]An embodiment of the invention is described below with reference to
drawings.

[0021]FIG. 10 is a block diagram illustrating a schematic structure of an
information recording and playback apparatus according to the embodiment.

[0022]The information recording and playback apparatus can selectively
record information on an optical disc 10 such as a DVD-R/RW, and a hard
disk drive (HDD) unit 14. Further, the information recording and playback
apparatus can temporarily record external information on the hard disk
drive unit 14, and then move (record) the information recorded on the
hard disk drive unit 14 to the optical disc 10. The hard disk drive unit
14 (external storage device) is not an indispensable constituent element
of the information recording and playback apparatus, but an optional
constituent element. Further, the information recording and playback
apparatus may have, for example, a semiconductor memory as an option, as
an information recording device. A semiconductor memory can be used as a
temporary information recording memory, instead of the hard disk drive
unit 14.

[0023]As illustrated in FIG. 10, the information recording and playback
apparatus has two drive units, that is, a disc drive unit 12, and the
hard disk drive unit 14. The disc drive unit 12 rotates and drives the
optical disc 10, and performs information reading and writing. The disc
drive unit 12 has a rotation control system, a laser drive system, and an
optical system for the optical disc 10. Further, the hard disk drive unit
14 drives a hard disk, and performs information reading and writing.

[0025]The information recording and playback apparatus also has an encoder
unit 20, a formatter 22, a decoder unit 36, and a control unit 26. The
encoder unit 20 encodes signals from a signal input unit 18. An encoded
output signal from the encoder unit 20 is converted into a predetermined
format by the formatter 22, and supplied to the data processor unit 16.
The formatter 22 is connected with a buffer memory 24, in which the
encoded output signal is stored. There are cases where the encoded output
signal from the encoder unit 20 is directly recorded on the hard disk of
the hard disk drive unit 14. When an encoded digital video signal and an
encoded digital audio signal are directly input, the encoder unit 20
directly supplies the encoded digital video signal and the encoded
digital audio signal to the formatter 22.

[0026]The format data from the formatter 22 is supplies to the hard disk
drive unit 14 or the data disc drive unit 12 through the data processor
unit 16, and recorded on the hard disk or the optical disc 10. Further,
the format data recorded on the hard disk or the optical disc 10 can be
recorded on the optical disc 10 or the hard disk through the data
processor unit 16 and the disc drive unit 12 (hard disk optical
disc/optical disc hard disk). Further, the data processor unit 16 can
perform editing to delete part of data recorded on the hard disk or the
optical disc 10, and connect parts of data.

[0027]The control unit 26 has an MPU (micro processing unit) or CPU
(central processing unit), a ROM in which control program is written, and
a RAM to provide a work area necessary for executing programs. Among
execution results of the MPU, the content to be notified to the user is
displayed on a display unit 28 of the information recording and playback
apparatus, or displayed on a monitor display connected to the information
recording and playback apparatus in an OSD (on-screen display) manner.
Further, the control unit 26 can connect to external networks through a
network interface 32. Thereby, the control unit 26 can take in an
electronic program guide through external networks.

[0028]Further, the control unit 26 controls the disc drive unit 12, the
hard disk drive unit 14, the data processor unit 16, the encoder unit 20,
and the decoder unit 36, on the basis of time data from a system time
clock (STC) 34. Although recording and playback operations are performed
in synchronization with the time clock from the STC 34, other operations
may be performed at timing independent of the STC 34.

[0029]Further, an input signal from an operation input unit is input to
the control unit 26. The operation input unit 3 is, for example,
operation switches provided on the main body of the information recording
and playback apparatus, and a remote controller which is independent of
the main body. As another example, the operation input unit 30 may be a
personal computer connected to the information recording and playback
apparatus by wired or wireless communication. The information recording
and playback apparatus performs playback, stop, recording, and editing,
based on operation inputs through the operation input unit 30.

[0030]The decoder unit 36 has a memory video decoder, an audio decoder,
and a video processor. A decoded output unit output from the decoder unit
36 is output from an signal output unit 38 to the outside.

[0031]FIG. 1 is a diagram illustrating relationship between the linear
velocity of triple-speed playback and data transfer rate by the
information recording and playback apparatus illustrated in FIG. 10.

[0033]The user bit transfer rate required for HD DVD-Video content is
33.24 Mbps. This rate is three times as high as the user bit data
transfer rate of current DVDs. Therefore, to ensure the data transfer
rate, it is necessary to rotate the DVD-R/RW/RAM disc at triple speed or
more. DVD-R/RW discs should be rotated with stability at a linear
velocity of at least 10.47 m/s in the case of single-layer discs and a
linear velocity of at least 11.52 m/s (triple speed or more) in the case
of double-layer discs, to record and playback the user data.

[0034]In the case of HD DVD-VR content, the user bit data transfer rate
can be selected from the recording modes of 22.16 Mbps and 11.08 Mbps for
extended recording, in addition to 33.24 Mbps. To perform recording and
playback at 33.24 Mbps, it is necessary to rotate the disc with stability
at triple speed or more in the same manner as HD DVD-Video content, to
record and play back the user data. The necessary data bit rates are as
illustrated in FIG. 1.

[0035]To rotate the disc at triple speed, it is necessary to set the
dynamic imbalance of the disc smaller than the disc of single-speed
playback. The dynamic imbalance is desirably 0.0044 gm for 12-cm discs,
and 0.0020 gm for 8-cm discs.

[0036]FIG. 2 is a diagram illustrating an example of a data playback
circuit which is formed by the disc drive unit 12, the data processor
unit 16, and the decoder unit 36 of the information recording and
playback apparatus illustrated in FIG. 10.

[0037]The data playback circuit can play back a DVD-R/RW at triple speed.
As illustrated in FIG. 4, the data playback circuit has a quadrant
photo-detector 101, an amplifier 102, an AC coupling 103, an equalizer
104, a low-pass filter 105, a level detector 106, a phase detector 107, a
demodulator 108, and a jitter measuring device 109.

[0038]The disc drive unit 12 has an optical pickup, and the optical pickup
has the quadrant photo-detector 101. An optical beam from the optical
pickup is focused onto the optical disc 10, and reflected light from the
recording film of the optical disc 10 is detected by the quadrant
photo-detector 101. A sum signal from the quadrant photo-detector 101 is
amplified to a predetermined signal amplitude by the amplifier 102, and
an HF signal is extracted by the AC coupling 103. The extracted HF signal
passes through the equalizer 104 for triple-speed playback, and its
frequency characteristic is adjusted. Next, noise component of the HF
signal is removed by the low-pass filter 105, the HF signal is digitized
by the level detector (slicer) 106, and a PLL clock of the HF signal is
detected by the phase detector 107. The digitized signal is processed by
the 8-16 demodulator 108, and bit data is played back. The jitter for the
PLL clock of the digitized signal before being processed by the decoder
108 is measured by the jitter detector 109.

[0039]The jitter of DVD-R/RW discs at single-speed playback is provided as
8.0% or less by specifications. The jitter is desirably 8.0% or less also
in triple-speed playback. In the signal processing circuit of the
information recording and playback apparatus according to the embodiment,
the margin of the playback system is designed with the jitter of
single-speed playback. This is because it is desirable that the system
can be used with same margin as the single-speed playback secured, in the
case of triple-speed playback.

[0040]FIG. 3 is a diagram illustrating an example of an equalizer
characteristic in triple-speed playback.

[0041]When a DVD-R/RW is played back at triple speed, the playback
frequency band is three times as high as that of the single-speed
playback. Therefore, the frequency band of the equalizer 104 when the
playback signal is digitized in playback is also three times as high as
that of the single-speed playback. In single-speed playback, an equalizer
characteristic of a signal with a frequency lower than 7.0 MHz is
provided. In triple-speed playback, it is necessary to provide an
equalizer characteristic of a signal with a frequency lower than 21.0
MHz, which is three times as high as the frequency in single-speed
playback.

[0042]In the case of using the equalizer 104 and the low-pass filter 105,
the allowable variation range of the gain desirably falls within ±1 dB
in the same manner as in single-speed playback.

[0043]Further, the allowable variation range of the group delay should be
set stricter than that n single-speed playback in consideration of
increase in frequency, and desirably falls within ±1.5 ns at 19.5 MHz
or less.

[0044]The gain in triple-speed playback should be set equivalent to that
in single-speed playback. The gain at 15.0 MHz is desirably 3.2±0.3 dB
in comparison with the gain of 0 MHz.

[0045]The low-pass filter 105 in triple-speed playback should be set to a
frequency three times as high as that in single-speed playback. In the
case of using a Bessel filter of order 6, the cutoff frequency of -3 dB
is desirably 24.6 MHz.

[0046]FIG. 4 is a diagram illustrating an example of a triple-speed
playback servo circuit included in the optical disk drive 12 of the
information recording and playback apparatus illustrated in FIG. 10.

[0048]In the case of DVD-R/RW, data is recorded on recording tracks
(groups). A recorded recording track is tracked by detection of phase
difference (DPD). In DPD, used is a differential signal between a sum
signal A of optical detector Ia and Ic forming the quadrant
photo-detector 101, and a sum signal B of optical detectors Ib and Id.

[0049]The sum signals A and B are amplified to a predetermined amplitude
by the amplifiers 201a and 201, respectively. Thereafter, the frequency
characteristics of the sum signals A and B are adjusted by the equalizers
202a and 202b, and binary waveforms at a predetermined threshold are
formed by the level detectors 203a and 203b. The phase comparator 204
extracts phase difference signals of the binary waveforms of the sum
signal A and the sum signal B. The phase comparator 204 extracts a phase
difference signal C1 in which the sum signal A has a phase advance of the
sum signal B, and a phase difference signal C2 in which the sum signal A
has a phase delay from the sum signal B. The phase difference signals C1
and C2 pass through the low-pass filters 205a and 205b, respectively, to
remove their high-frequency components, and a phase difference signal is
generated by the differential amplifier 206. Tracking control is
performed with the phase difference signal used as a tracking error
signal.

[0050]Although the cutoff frequency of the low-pass filters 205a and 205b
in single-speed playback is 30 kHz, it is necessary to increase the
frequency in triple-speed playback. In the case of using a first-order
filter, the cutoff frequency of -3 dB in triple-speed playback is
desirably set to 56 kHz.

[0051]FIG. 5 is a diagram illustrating an example of an axial focus servo
characteristic for triple-speed playback.

[0052]Although the maximum runout acceleration in single-speed playback is
8 m/s2, the maximum runout acceleration in triple-speed playback is
desirably 32 m/s2 to secure the margin of the disc. The runout of
the disc is desirably 300 μm or less, and the focus error (focus servo
residual quantity) when the focus servo is effective desirably falls
within the range of not exceeding ±0.23 μm when measured at 10 kHz
or less. The cutoff frequency in this case is 4.0 kHz at -3 dB.

[0053]FIG. 6 is a diagram illustrating an example of a radial tracking
servo characteristic.

[0054]Although the maximum eccentricity acceleration in single-speed
playback is 1.1 m/s2, the maximum eccentricity acceleration in
triple-speed playback is desirably 4.0 m/s2 to secure the margin of
the disc. The eccentricity quantity of the disc is desirably 50μ or
less, and the tracking error quantity (focus servo residual quantity)
when the focus servo is effective desirably falls within the range of not
exceeding ±0.022 μm when measured at 2.1 kHz or less. The cutoff
frequency in this case is 4.5 kHz at -3 dB.

[0055]FIG. 7 is a diagram illustrating an example of disc discrimination
processing in which triple-speed recording is possible by the information
recording and playback apparatus illustrated in FIG. 10.

[0056]To record HD DVD/VR content, it is necessary that the narrow burst
cutting area (NBCA) of the disc is valid. The control unit 26 of the
information recording and playback apparatus determines whether the NBCA
of the loaded disc (ST101) is valid or not (ST102). Specifically, the
disk drive 12 and the data processor unit 16 of the information recording
and playback apparatus read an NBCA flag on the DVD-R/RW disc, and the
control unit 26 determines the validity of the NBCA (ST102). When the
control unit 26 determines that the NBCA of the loaded disc is valid
(NBCA is recorded) (ST102, YES) and the maximum recording speed of the
disc is triple-speed or more (at least triple-speed as high as the
predetermined recording speed [normal recording speed]) (ST103) (ST104,
YES), the disk drive 12 and the data processor unit 16 record the HD
DVD/VR content on the disc at triple recording speed (ST104).

[0057]A revision number (recording speed information) of specifications
providing the recording speed is recorded on discs. Specifically, the
disk drive 12 and the data processor unit 16 read the revision number,
and the control unit 26 determines at which speed the disc can perform
recording. When recording speed information of triple speed or more is
supported, the disk drive 12 and the data processor unit 16 record the HD
DVD/VR content on the disc in real time.

[0058]When the control unit 26 determines that the NBCA of the loaded disc
is invalid (NBCA is not recorded) (ST102, NO), it is impossible to record
the HD DVD/VR content on the disc in real time (ST106).

[0059]A copyright protection method called AACS is used for HD DVD/VR
content for copyright protection of the content. This is because NBCA
information is referred to by AACS. Further, also when the disc supports
only a recording speed lower than triple speed (ST104, NO) although the
NBCA is valid (ST102, YES), it is impossible to record the HD DVD/VR
content on the disc at triple speed in real time (ST107).

[0060]FIG. 8 is a flowchart illustrating processing of recording HD DVD/VR
content on a disc which only supports a recording speed lower than
triple-speed recording by the information recording and playback
apparatus of the embodiment.

[0061]When the control unit 26 of the information recording and playback
apparatus determines that MBCA of the loaded disc (ST201) is valid (NBCA
is recorded) (ST202, YES) and that the maximum recording speed of the
disc is less than triple speed (less than three times as high as the
predetermined recording speed [normal recording speed]) (ST203) (ST204,
NO), it is impossible to record the HD DVD/VR content on the disc at
triple speed in real time (ST207). Specifically, when the recording speed
supported by the disc is lower than the triple speed, it is impossible to
record the HD DVD/VR content on the disc at triple speed in real time
(ST207).

[0062]Therefore, the control unit 26 and the data processor unit 16
temporarily store the HD DVD/VR content in the hard disk drive unit 14,
and the data processor unit 16 and the disc drive unit 12 record the HD
DVD/VR content recorded in the hard disk drive unit 14 at a data transfer
rate lower than the triple speed.

[0063]For example, data of the recorded HD DVD/VR content is transferred
to the data processor unit 16 for a double-speed recording disc at a
speed corresponding to double speed. Thereby, it is possible to record
the HD DVD/VR content on the double-speed recording disc.

[0064]FIG. 9 is a flowchart illustrating playback processing of HD DVD/VR
content recorded on a disc by the information recording and playback
apparatus illustrated in FIG. 10.

[0065]To play back HD DVD/VR content recorded on a disc, it is necessary
that the narrow burst cutting area (NBCA) of the disc is valid. When the
NBCA is invalid, the AACS is invalid and thus it is impossible to
playback the HD DVD/VR content recorded on the disc. When the NBCA is
valid, the AACS is valid. The control unit 26 of the information
recording and playback apparatus determines whether the NBCA of the
loaded disc (ST301) is valid or not (ST302). Specifically, the disk drive
12 and the data processor unit 16 of the information recording and
playback apparatus read an NBCA flag on the DVD-R/RW disc, and the
control unit 26 determines the validity of the NBCA (ST302). When the
control unit 26 determines that the NBCA of the loaded disc is valid
(NBCA is recorded) (ST302, YES), that HD DVD/VR content is recorded on
the disc (ST303), and the maximum recording speed of the disc is triple
speed or more (at least triple-speed as high as the predetermined
recording speed [normal recording speed]) (ST304, YES), the control unit
26 plays back the HD DVD/VR content recorded on the disc (ST305), since
the disc is compliant with triple-speed playback.

[0066]When the control unit 26 determines that the maximum recording speed
of the disc is lower than the triple speed (ST304, NO) although it
determines that the NBCA of the loaded disc is valid (NBCA is recorded)
(ST302, YES), the control unit 26 plays back the HD DVD/VR content
recorded on the disc (ST305), if identification information compliant
with triple-speed playback is recorded on the disc (ST306, YES). When the
control unit 26 determines that identification information compliant with
triple-speed playback is not recorded on the disc (ST306, NO),
triple-speed playback is not supported, and thus a problem may occur in
playback of the HD DVD/VR content. Therefore, the control unit 26
determines that the NBCA of the loaded disc is valid (NBCA is recorded)
(ST302, YES), that the maximum recording speed of the disc is lower than
the triple speed (ST304, NO), and no identification information compliant
with triple-speed playback is recorded on the disc (ST306, NO), and does
not play back the HD DVD/VR content recorded on the disc.

[0067]The identification information compliant with triple-speed playback
is preferably recorded on the disc in advance as physical format
information of the disc, or embossed on the disc.

[0068]For example, identification information indicating triple-speed
playback and single-speed playback is recorded by the following bits.

[0069]1b: triple-speed playback

[0070]0b: single-speed playback

[0071]or

[0072]1b: triple-speed playback and single-speed playback

[0073]0b: single-speed playback

[0074]DVD-RAM discs do not have an NBCA. DVD-RAM discs have a BCA instead.
Therefore, when the information recording and playback apparatus records
HD DVD/VR content on a DVD-RAM disc or plays back HD DVD/VR content
recorded on a DVD-RAM disc, the information recording and playback
apparatus detects whether a BCA flag exists or not, instead of the NBCA
flag described above. Thereby, the information recording and playback
apparatus according to the embodiment can record HD DVD/VR content not
only on DVD-R/RW discs but also on DVD-RAM discs, and play back HD DVD/VR
content recorded on DVD-RAM discs.

[0075]Next, the maximum data transfer rate is explained. The maximum data
transfer rate is provided by specifications as physical format
information of discs. In DVD-R/RW discs, user data is recorded later.
Therefore, the maximum data transfer rate of the disc is not provided in
DVD-R/RW discs. For example, a flag indicating the data transfer rate is
formed of 4 bits.

[0076]0010b: 10.08 Mbps (corresponding to single-speed playback)

[0077]1111b: Not provided

[0078]The maximum data transfer rate corresponding to triple-speed
playback may be set only for DVD-R/RW discs which can be played back at
triple speed.

[0079]Although support for at least triple speed is mentioned as a
condition for recording and playback of HD DVD/VR content in the above
explanation, the embodiment is not limited to it. For example, among HD
DVD/VR content, there is HD DVD/VR content for which double-speed
playback suffices. Specifically, the maximum data transfer rate
corresponding to double-speed playback may be set as a condition for
recording and playback of HD DVD/VR content.

[0080]0000b: 10.08 Mbps (corresponding to single-speed playback)

[0081]0011b: 20.16 Mbps (corresponding to double-speed playback)

[0082]0100b: 30.24 Mbps (corresponding to triple-speed playback)

[0083]1111b: Not provided

[0084]The flag of the maximum data transfer rate of the disc may be used
as a flag of triple-speed playback.

[0085]According to the information recording playback apparatus of the
embodiment, when HD DVD/VR content is recorded on a disc of a recording
speed higher than triple speed, it is possible to record the content on
the disc at a recording speed higher than triple speed.

[0086]For example, the information recording playback apparatus may record
a triple-speed playback content on a disc compliant with octuple-speed
(8×) recording at octuple speed. A predetermined quantity of data
of the content is stored in the buffer memory of the information
recording playback apparatus, and the data is recorded on the disc at
octuple speed. When stored data of the buffer memory is run out, the
information recording playback apparatus waits until data is stored in
the buffer memory, and octuple-speed recording is performed again. By
intermittently performing recording each time a predetermined quantity of
data is stored in the buffer memory, it is possible to record data at a
speed higher than the triple speed.

[0087]As another example, the information recording playback apparatus can
temporarily store HD DVD/VR content in the hard disk drive unit 14. Since
the HD DVD/VR content is recorded on the hard disk drive unit 14, it is
possible to record the HD DVD/VR content on the optical disc at a data
transfer speed higher than the triple speed.

[0088]For example, HD DVD content recorded on the hard disk drive unit 14
is transferred to an octuple-speed disc at a data transfer rate
corresponding to the octuple speed, and thereby the HD DVD-VR content can
be recorded on the disc at octuple-speed. Also in this case, it is
required that the NBCA of the disc is valid.

[0089]According to the embodiment, it is possible to appropriately record
HD DVD content on DVD-R/RW RAM discs. Further, it is possible to
appropriately play back HD DVD content recorded on DVD-R/RW/RAM discs.

[0090]While certain embodiments of the invention have been described,
these embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel methods
and systems described herein may be embodied in a variety of other forms:
furthermore, various omissions, substitutions and changes in the form of
the methods and systems described herein may be made without departing
from the spirit of the inventions. The accompanying claims and their
equivalents are intended to cover such forms or modifications as would
fall within the scope and spirit of the inventions.